When the driven wheels of a wheeled vehicle spin with respect to the surface over which the vehicle is travelling, lateral instability or loss of directional control of the vehicle may result. The driven wheels may spin when excessive torque is applied to the wheels, for instance during rapid acceleration of the vehicle, or when the vehicle passes over a surface having a relatively low coefficient of friction, for instance ice, mud, snow and gravel.
Traction control systems are known which detect excessive wheel spin and which reduce the drive supplied to the driven wheels to stop the driven wheels from spinning excessively, thereby allowing control of the vehicle to be maintained.
The performance of a traction control system is generally a compromise. For low friction surfaces, the traction control system should have a low entry threshold, that is the amount of wheel spin that is acceptable before the traction control system operates to reduce the drive supplied to the driven wheels. For high friction surfaces, a higher entry threshold is preferable so as to provide improved acceleration performance of the vehicle.